What is boolean in C?

A boolean is a data type in the C Standard Library which can store true or false. Every non-zero value corresponds to true while 0 corresponds to false.

The boolean works as it does in C++. However, if you don’t include the header file​ stdbool.h, the program will not compile.

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Another option is to define our own data type using typedef, which takes the values true and false:

typedef enum {false, true} bool;

However, it is safer to rely on the standard boolean in stdbool.h.

Examples


1. Using the header file stdbool.h

#include <stdio.h>
#include <stdbool.h>
int main() {
  bool x = false;
  if(x){
    printf("x is true.");
  }
  else{
    printf("x is false.");
  }
}

2. Using typedef

#include <stdio.h>
typedef enum {false, true} bool;
int main() {
  bool x = false;
  if(x){
    printf("x is true.");
  }
  else{
    printf("x is false.");
  }
}

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